These little critters are Blue Throat Ascidians (Clavelina australis) and live in compound clusters.

They look like a nest of little chicks of some bizarre bird with mouths agape chirping for food.

Actually just like birds these critters are chordates and though they don’t really have a backbone they do have long nerve running the length of their body making for a rudimentary spinal cord.

Photo: Robert Rath, ‘Mouths Agape’ 1/200s f/18 ISO100 100mm